The present invention relates to a magazine for storing toolholders with tools mounted therein for machine tools, in particular machining center type machines.
A magazine of this type has been known already as part of a machine tool (leaflet "Compact-Center nb-h 65 of Messrs. Huller-Hille GmbH, Werkzeugmaschinend).
In this magazine, the toolholder support takes the form of a horizontally seated disk which has the toolholder sockets provided at its periphery. The sockets are open at the side, i.e. at the outer periphery.
The toolholders stored in the toolholder sockets are secured in the latter by means of one locking member each. For this purpose, the said locking members bear against a circumferencial portion of the toolholders projecting from the toolholder sockets.
The design and arrangement of the locking members is such that they are automatically held in their locking position and that only the toolholder which has been previously brought into a pre-determined changing position can be automatically released.
Such releasing is caused by a stop which is caused by the relative movement between the magazine disk and the tool spindle necessitated for the performance of a tool change to act upon the locking member and to move the latter into its releasing position.
In this known design, the locking members, due to the particular construction, project relatively far beyond the periphery of the magazine disk which may be disadvantageous, for instance if the arrangement is to be enclosed.
Moreover, the locking members must be provided at the toolholder support and/or the magazine disk between two neighbouring toolholder sockets, so that a relatively large mutual distance between the toolholder sockets becomes necessary.
Finally, the contact pressure exerted by the locking members upon the toolholders and required for centering the latter in the toolholder sockets is released already in the initial phases of the changing procedure, a fact which may impair the coaxial alignment between toolholder and tool spindle during the changing operation.
Now, it is an object of the present invention to provide a magazine in which the arrangement of the at least one locking member associated with the toolholder sockets eliminates the drawbacks of the known magazine construction.
This arrangement is to ensure that even large toolholders with their correspondingly heavy tools mounted therein will be held by the locking member at the toolholder support in perfectly aligned position during the changing operation until the drivers provided at the front face of the tool spindle engage positively the grooves in the periphery of the driver flange of a toolholder to be exchanged, thus assuming the function of aligning the toolholder to be exchanged coaxially in relation to the tool spindle, a function which had been performed to this moment by the locking member.
Accordingly, this problem is solved by having the locking members of the magazine construction of the invention, as well as their holders, arranged away from the periphery of the toolholder support.
The fact that the locking members engage the driver flange of the toolholders, preferably from the front face of the flange, creates the possibility to use the locking members both as aligning and retaining means. This offers the particular advantage of a perfect alignment and retention of the toolholders in the toolholder sockets of the toolholder support even when heavy tools are mounted therein and withdrawn by the tool spindle from the toolholder support, for instance from below.
In addition, contrary to the known construction, the individual locking mechanisms will work also when the toolholder support is not designed as a disk but for example as a longitudinal block arranged for linear movement in both the parallel and perpendicular directions relative to the tool spindle axis.
The locking member associated with each toolholder socket may for instance take the form of a cylindrical lug engaging a matching bore in the driver flange.
According to an advantageous improvement of the invention two locking holders per toolholder socket may be arranged on a common holder to engage oppositely arranged recesses in the flange.
In this case, no special recesses in the driver flange of the toolholders will be required when the locking members are matched in shape and dimensions to the grooves in the driver flange. Thus, it is possible to store in the magazine even tools already available in the shops without the need to change their driver flange in any manner whatever.
Furthermore, one holder may carry also the locking members of at least two neighbouring toolholder sockets so that the latter can be moved jointly into and/or out of their releasing position.
In a preferred embodiment of the invention, the toolholder support takes the form of a rotatable and at least axially displaceable toolholder disk arranged concentrically to the tool spindle. In this case, it is advantageous to have the locking members arranged at the holders of the individual toolholder sockets.
Also, it is advantageous in this case to give the end of the holders nearest the periphery of the disk the shape of a fork, so that the arms of the fork encompass a lateral portion of the toolholders present in the toolholder sockets. The locking members engaging the grooves of the driver flange of the toolholders to be locked may in this case be formed simply by bent-off endportions of the fork arms.
A second embodiment of the holder, the stop coacting with all stop members of any one holder may be provided in stationary arrangement at the machine frame in the vertical plane of movement of the tool spindle.
However, a particular advantage is provided by the arrangement and design of the stop. In this case, the holder is immediately released by the stop when the transfer of a toolholder from the toolholder support to the tool spindle has been completed so that the holder may immediately return into its waiting position in which the locking members are held in their locking position.
The design of the locking members ensures that when a toolholder is transferred to the tool spindle the drivers of the latter can engage the grooves of the driver flange of the toolholder transferred before the locking members are withdrawn from the grooves in the flange and moved into their releasing position for performing the exchange. Thus, the perfect coaxial alignment and retention of the toolholder in the respective toolholder socket is ensured in any phase of the axial transfer motion of the tool spindle relative to the toolholder.
As described before, the holders of the locking members may also take the form of individual, preferably sector-shaped elements each fixed separately at the toolholder support. However, when the magazine is designed as a disk, a particularly advantageous embodiment is where the holders take the form of a slotted steel plate imposed upon the front face of the toolholder.
Another advantageous embodiment of the magazine provides the possibility to remove and/or insert toolholders into or from the toolholder support also by hand, for instance for the purpose of exchanging defective tools while the tool spindle is working with a toolholder withdrawn from one toolholder socket. To this end, it is advantageous to provide operating means by which the holders can be moved into their releasing position after the toolholder support and/or the magazine disk has been adjusted to bring the toolholder socket of a toolholder to be exchanged in alignment with the operating means.
Other features and details of the invention will be apparent from the following description of an embodiment shown in the drawing and of possible modifications of the design of the invention and from the claims.